1. Field of the Invention
This invention relates to engine-driven equipment, for example, an engine-driven electric generator, and more particularly to an improvement in electrical circuitry and fuel supply systems therefor which avoids fuel and battery energy wastage.
2. Description of Related Art
In engine-driven electric generators, compressed gas is generally used as the fuel for driving the generator unit. In addition, a battery is often used to facilitate starting of the engine. In such gas powered generators, auxiliary equipment such as electrically operated cooling fans for preventing the generator unit from overheating and electrically operated lubricating pumps to pump lubricating oil to the gas engine are required.
In general, stopping such a compressed gas powered engine involves interrupting the electrical circuit to the glow plugs by throwing a main switch to halt the flow of electricity to the glow plugs. When the engine is stopped due to lack of fuel or some other cause before the main switch has been thrown to cut power to the engine, the generator stops generating electricity but the electrical circuits remain closed and the above auxiliary equipment continues to run off of battery power. Because many types of engine-driven equipment are allowed to run unattended, the auxiliary equipment may end up operating for a long period of time even after the engine has been turned off. This results in a disadvantageous running down of the battery.
In the case of certain auxiliary devices which consume a great deal of electrical power, such as illumination devices, the engine-driven generator supplies electricity to both the equipment and the battery in a so-called free battery charging system. If the engine stops as described above, then power is supplied only from the battery, which then runs down especially rapidly.
Furthermore, in addition to the problem of battery energy wastage when the engine stops without throwing the main switch, a different problem arises when the engine is turned off using the main switch. The engine shut-off using the main switch causes engine fuel remaining within the fuel lines to back up and be expelled, thereby wasting engine fuel.